Guard for x-ray tubes



G. (Jr-JOHNSTON AND L. S. UPHOFF.

GUARD FOR X-RAY TUBES.

APPLICATION FILED AUG-2|, I9I9- Patented Dec. 20, 192i.

2 SHEETS-SHEET 2- UNITED STATES PATENT "oFFicE.-

. ,9" GEORGE C. JOHNSTON, OF PITTSBURGH, PENNSYLVANIA, AND LESLIE S'fiUfHOFF, 0]!

SCHENECTADY, NEW YORK.

GUARD FOR X-RAY TUBES.

Specification of Letters Patent.

Application filed August 21, 1919. Serial No. 319,038.

' rman UNDER THE ACT or MARCH 3, 1883, 2a sum-LL, 625

TON and LESLIE S. UPHOFF, citizens of the United States, and residents of Pittsburgh, Pa., and Schenectady, N. Y., respectively,

' stationed at Washington, D. C., have invented an Improvement in Guards for X-Ray Tubes, of which the following is a specification.

The invention described herein may be used by the Government, or any of its oflicers or employees in prosecution of work for the Government, or by anyother person in the United States without payment of any royalty thereon.

This invention relates to X-ray machines and, particularly, to means for protectingv the terminals of the X-ray tube, so that neither the patient nor anyone else near the tube can he accidentally electrically shocked.v

The terminals of an X-ray tube carry high tension current while the machine is in operation, and many accidents occur with the usual construction of exposed or unguarded tion is to provide grounded metallic pro-- terminals, by persons being shocked thereby.

The basic object therefore, of our inventecting means for the terminals of an X-ray tube.

further object is to provide protecting means whichwill not cease to function unless entirely removed from the tube stand. A further object is to provide a structure which. will not be unsightly or,cumbersome, and which will not add appreciably to the space occupied by the X-ray tube-stand.

A further object is to construct the guards so that they will serve the additional funetion of supports of the X-ray tube, thus doingaway with the'tubesupports ordinarily used on the tube stand.

A further object is to provide, in combination with a guard of the character'described, a yieldingliy and resiliently support ed socket for the a -ray tube, thus obviating the tendency of the screw base of the X-ray tube being broken off in the operation of screwing the same'in its socket, which is likely to happen with a rigidly supported socket. p v I Incidentally, the guards serve to cut off some of the stray radiation which'emanates from the side' openings in the lead glass grounded metallic protecting means is al ways between the dangerous tube-terminals and any person near the tube ends, thus affording absolute protection. 7

The in'ventionresides, further, in interposing fbetween the terminals and the grounded metallic protectors sufficient insu lation, so'that the device may be made small enough to be practical and convenient. If only air were used for insulation, the large size necessary would make the device ex-. tremely bulky and unwieldy. v

The accompanying drawings clearly disclose an exemplary construction capable of carrying out the underlying principles of the invention. Like reference characters designate corresponding parts in all the views. Briefly described Figure 1 is a view in side elevation of an X-ray tube-stand equipped with our improvements;

Fig. 2 is a view in end elevation of one of the guards, looking at the open end thereof,

Fig. 3 is a fragmentary central vertical sectional view of the protecting tubes carried by the cathode guard; Fig. 4 is a collective view of the two guards, one for the cathode end of the X-ray tube and the other for the anode end thereof; and

Fig. 5 is a detail view in end elevation,

looking at the open end of one of the tubuscrewed into one end thereof, a bar or plate .4 of insulating material vertically disposed at the end of the cylinder 2 opposite the plug end thereof, and a clip 5, all of whlch Patented neceo, 1921.

- parts-*will be more particularly described hereinafter. While we have-shown the cyl- .inder 2 and the plug 3 as two pieces, it will a be understood that the tube may be made with an integral closed end, as by molding.

The metal body -1 is a shell comprising, pre'ferably, a base or .floor 6, the side walls 7, 7, and the end wall 8. The side walls 7, 7

at one end, are upwardly extended, as shown toward one end thereof. The other end of the cylinder 2 is supported by a vertically disposed-insulating iece l, which may be with a metal part ofthe tube-stand 14. The

secured to the cylin er 2 and metallic body 1 in any suitable manner, as by screws 11. The insulating piece 4, at its bottom, is cut away centrally, as shown at 12.

.A metallic clip 13 connects the metal body 1 with the metal parts of the tube-stand 14.

The clip contacts with the floor 6 of the metal body-1 at the open end thereof, and

clip may be attached to the tube-stand by screws 15. Themetal body. 1, thus electrically grounded through the tube-stand 14:, is always between the dangerous tube-terminals and any person near the tube-ends, and thus affords absolute protection. It should be noted that even if the insulation 2 breaksdown, the protective value f the guardsv is not impaired. Also, if the tubestand is not deliberately grounded by a wire,

or if'this wire accidentally comes oil, the tube-stand isalways as well grounded byv means of the floor as is any person near it, and there would, therefore, be no difference in. potential between the person and the metal guards. l

One of the cylinders 2 (which may be termed the cathode cylinder) carries interiorly a screw socket'16, into which an X-ray tube 17, provided with the usual screw base, may be screwed, The. socket 16 is carried by a member 18, which, in turn, is supported from the plug 3 by a leafspring 19. The socket 16 is thus yieldingly and resiliently supported. It will thus be seen that, in

, screwing an X-ray tube into said socket, the

danger of breaking the screwbase from the tube (which wouldbe apt to occur if the socket were rigidly supported) is obviated. Carried by the member 18 and projecting axlally into the'socket 16 is a sliding pin 20 projected into the socket 16 by a spring 21 bearing against the head of the pin and disposed in a recess in said member 18, as shown in Fig. 4. By the construction described, it will be noted that an X-ray'tube screwed into the socket 16may .be turned one and one-quarter turns after it contacts with the pin 20, thusenabling thd focal spot of the target to be pointed in any direction.

Two electrical wires 22, 22 are connected to the electrical terminals of the socket 16, as shown in Fig. 4c, and extend up through the insulating and protecting tube 23, to the insulating plug 24. carrymg the hollow metal rods 25, 25, (see Fig. 3) into whlch the upper ends of the wires 22, 22 pro ect. A removable connector 26 seats on top of the plug 24.

The tube 23 carries toward 1ts upper end a hook 27, which serves a dual function, viz., it retains in position the plu 24 and also prevents the connector 26 be ng pulled oif by upward stress on the mm 23, whichpasses over'an overhead pulley and lsalways taut. It will be understood that, as usual,

that portion of the tube-stand carrying the tube is tiltable.

Suitable means are provided to the open end of one of the cylinders 2for holding the- X-ray tube from turning. In this instance, such means comprises two curvilinear arms 29, 29 pivoted at their. lower ends, as at 30, 30, to the cylinder 2, at the open end thereof, and spring-pressed toward each other by a spring 31 secured to andconnectlng sald arms atthe top thereof. a U

The arms 29, 29 are provided, intermediate their length, with rubber inserts 32, 32, constituting cushioning elements, which bear against the X-raytube 17 in use.

Disposed interiorly of the anode guard 2 is a resilient clamp, comprising a plurality of spring metal fingers 33. In this instance, this spring clamp ispreferably an integral member stamped out of a blank of sheet metal and bent up to shape. The spring metal clamp issecured as by screws 34, to a metalbar or rod 35 inclosed by an insulating tube 36. The rod or bar 35 maybe secured against longitudinal movement by an suitable means, in this instance by a screw 3 carried by the tube 36. At its upper end, the rod 35 is provided with a perforation 38, so that the corresponding end of the wire 28. may be secured thereto.

Having described our invention, what we claim as new and desire. to secure by Letters Patent, is 1. The combination, with an X-ray tube' stand, provided with the usual X-ray tube, of grounded metallic guards for said tube, carrying a pair of insulating members encircling said tube.

2. The combination, .withan X-ray tubestand, provided with the usual X-ray tube, of grounded metallic guards for said tube, carrying a air of insulating cylinders in which said 4 -ray tube is disposed.

3. The combination, with an X-ray tubestand, provided with the usual X-ray tube, of grounded metallic guards for said tube, carrying insulating cylinders in which said 1 tube is disposed, and insulating plugs closing one end of said tubes. 2 v 4. In an X-ray tubetand, provlded with the usual X-ray tube, an insulating cylinder.-

in which said tube is disposed, a tube-holder disposed in said cylinder, and a sliding contact pin projecting axially into said tube holder.

5. In an X-ray tube-stand, provided With the usual X-ray tube, an insulating cylinder in which said tube is disposed, a tube-holder. disposed in said cylinder, and a springpressed pin projecting axially into said tube holder.

6. In an X-ray tube-stand, provided with the usual X-ray tube, an insulating hollow member in which said tube is disposed, and means for yieldingly supporting one end of said tube, comprising a pair of arms pivoted at one end thereof to said member and spring pressed toward each other.

7. In an X-ray tube stand, provided with the usual X-ray tube, a pair of insulating hollow members in which the respective ends of the tube are disposed, a resiliently supported tube socket mounted in one of said members, a pair of tube engaging arms pivoted to the other of said members and a resilient clamp disposed within said latter member.

GEORGE C. JOHNSTON. LESLIE S. UPHOFF. 

